須田 康一

BACKGROUND: The use of the hinotori™ Surgical System (hinotori) in distal pancreatectomy (DP) is new compared to the da Vinci™ Surgical System (DVSS). The hinotori is equipped with mechanisms distinct from those of DVSS, and comprehensive reports detailing the surgical techniques and outcomes associated with hinotori in DP (hinotori-DP) are lacking. This study aimed to compare the outcomes of DP using the hinotori and DVSS (Xi system), focusing on differences in settings and techniques between the two methods. METHODS: This study retrospectively investigated consecutive patients who underwent robotic DP from April 2010 (the introduction of robotic DP at our institute) to July 2024. The analysis excluded patients who underwent spleen-preserving procedures or procedures performed using robotic platform other than hinotori or daVinci Xi. The hinotori-DP cases were compared with those performed using DVSS (DVSS-DP). The techniques used in hinotori-DP were examined in more detail. RESULTS: A total of 75 robotic DP cases (11 with hinotori and 64 with DVSS) were analyzed in this study. Different port configurations and techniques, including a lesser curvature approach, were used in the hinotori-DP compared to DVSS-DP. The operation time was relatively shorter in the hinotori-DP group (299 vs. 366 min, p = 0.095), and the postoperative complication rates were comparable (pancreatic fistula: 27 % vs. 30 %, p = 0.871; Clavien-Dindo Grade ≥3a complications: 18 % vs. 19 %, p = 0.964) between the two groups. CONCLUSION: The hinotori-DP can be safely performed by focusing on the unique characteristics of the hinotori surgical system.

Colorectal cancer (CRC) is well characterized in terms of genetic mutations and the mechanisms by which they contribute to carcinogenesis. Mutations in APC, TP53, and KRAS are common in CRC, indicating key roles for these genes in tumor development and progression. However, for certain tumors with low frequencies of these mutations that are defined by tumor location and molecular phenotypes, a carcinogenic mechanism dependent on BRAF mutations has been proposed. We here analyzed targeted sequence data linked to clinical information for CRC, focusing on tumors with a high tumor mutation burden (TMB) in order to identify the characteristics of associated mutations, their relations to clinical features, and the mechanisms of carcinogenesis in tumors lacking the major driver oncogenes. Analysis of overall mutation frequencies confirmed that APC, TP53, and KRAS mutations were the most prevalent in our cohort. Compared with other tumors, TMB-high tumors were more frequent on the right side of the colon, had lower KRAS and higher BRAF mutation frequencies as well as a higher microsatellite instability (MSI) score, and showed a greater contribution of a mutational signature associated with MSI. Ranking of variant allele frequencies to identify genes that play a role early in carcinogenesis suggested that mutations in genes related to the DNA damage response (such as ATM and POLE) and to MSI (such as MSH2 and MSH6) may precede BRAF mutations associated with activation of the serrated pathway in TMB-high tumors. Our results thus indicate that TMB-high tumors suggest that mutations of genes related to mismatch repair and the DNA damage response may contribute to activation of the serrated pathway in CRC.

BACKGROUND: In the field of abdominal surgery, including colorectal cancer surgery, robotic surgery has become widespread, and the introduction of new robotic platforms is increasing. As a result, the incidence of subcutaneous emphysema (SE) as a postoperative complication has increased; however, the causes, grade, and perioperative course of SE have not been definitively examined. Therefore, we aimed to evaluate potential risk factors of SE after robotic colorectal cancer surgery. METHODS: Between November 2022 and March 2024, 244 consecutive patients who underwent robotic colorectal cancer surgery using the da Vinci Xi (n = 190) or the hinotori™ platform (n = 54) were retrospectively analyzed. Risk factors associated with postoperative SE were assessed by multivariate analysis using logistic regression models. Moreover, the grade of SE and its perioperative course were investigated based on the two robotic platforms. RESULTS: Postoperative SE was observed in 95 patients (38.9%). Nine patients (3.7%) had severe SE. The risk factors for SE were female sex, older age (≥ 80 years), and maximum intraabdominal pressure (max IAP) with CO2 insufflation > 10 mmHg (odds ratio [95% confidence interval]: 1.981 [1.105-3.552], p = 0.022; 2.765 [1.310-5.835], p = 0.008; and 13.249 [1.227-143.020], p = 0.033, respectively). Additionally, the incidence of SE when using the hinotori™ platform was significantly lower than when using the da Vinci Xi platform (0.302 [0.135-0.667], p = 0.004). CONCLUSIONS: Max IAP with CO2 > 10 mmHg was associated with SE during robotic colorectal cancer surgery. Compared with the use of da Vinci Xi, the use of hinotori™ was associated with fewer incidences of postoperative SE, especially in females and older patients (≥ 80 years).

Pelvic arteriovenous malformation (AVM) is a rare vascular condition with diverse clinical manifestations. Treatment-related decision-making is difficult for concurrent AVMs and colon cancer. Interventional radiology is effective for colon cancer patients with pelvic AVM. Herein, a 77-year-old man presented with fatigue. Computed tomography revealed thickening of the sigmoid colon wall without lymph node swelling or distant metastasis, confirming irregularly dilated pelvic blood vessels. Preoperative transcatheter embolization of the AVM was initially performed. Then, laparoscopic sigmoidectomy was performed without complications following confirmation of AVM shrinkage via computed tomography. The patient was discharged without complications. Thus, preoperative pelvic AVM embolization in patients with sigmoid colon cancer may facilitate safe minimally invasive surgery.

Background: In Japan, the hinotori™ surgical robot system (Medicaroid Corporation, Kobe, Japan) was approved for gastrointestinal surgeries in October 2022. This report details our initial experience performing liver resection using the hinotori™ system. Methods: Ten patients, who were assessed as cases that would benefit from the robot-assisted procedure, underwent liver resections using the hinotori™ system at Fujita Health University, Okazaki Medical Center, between August 2023 and October 2024. The backgrounds (patient, tumor, and liver function conditions, along with types of liver resections and previous surgical procedures) and short-term outcomes (operation time, blood loss, postoperative complications, open conversion, length of hospital stay, and mortality) of the cases were evaluated. Results: Eight cases of partial liver resection, one extended left medial sectionectomy, and one left hemi-hepatectomy were performed. Six cases of hepatocellular carcinomas, three cases of liver metastases, and one case of hepatolithiasis were included. There were seven male and three female patients with a median age of 70 years. Three physical status class III and seven class II patients were included. The median body mass index was 24. Five patients had previous upper abdominal surgical histories and five patients had liver cirrhosis. The median operation time was 419.5 min, and the median intraoperative blood loss was 276 mL. An open conversion in one hepatocellular carcinoma case was carried out due to bleeding from collateral vessels in the round ligament. The median length of hospital stay was 7.5 days. A grade IIIa complication (delayed bile leakage) was developed in one case. All patients with tumors underwent R0 resection. There were no cases of mortality. Conclusions: Liver resection using the hinotori™ system was feasibly performed. This study reports the first global use of the hinotori™ system for liver resection.